/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community License, Version 2.0 (the "License"); you may not use this file
    * except in compliance with the License. You may obtain a copy of the License
   * at:
   *
   *   http://opensource.org/licenses/ecl2.txt
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
   * License for the specific language governing permissions and limitations under
   * the License.
   *
   */
  
  package org.opencastproject.util.data.functions;
  
  import static org.opencastproject.util.EqualsUtil.eq;
  
  import java.util.List;
  import java.util.Optional;
  import java.util.function.Function;
  
  /** Various functions not directly bound to any type. */
  public final class Misc {
    private Misc() {
    }
  
    private static <T extends Throwable, A> A castGeneric(Throwable t) throws T {
      // The cast to T does not happen here but _after_ returning from the method at _assignment_ time
      // But since there is no variable assignment. The Throwable is just thrown.
      throw (T) t;
    }
  
    /**
     * Throw a checked exception like a RuntimeException removing any needs to declare a throws clause.
     *
     * This technique has been described by James Iry at
     * http://james-iry.blogspot.de/2010/08/on-removing-java-checked-exceptions-by.html
     */
    public static <A> A chuck(Throwable t) {
      return Misc.<RuntimeException, A> castGeneric(t);
    }
  
    /** {@link #chuck(Throwable)} as a function. */
    public static <A extends Throwable, B> Function<A, B> chuck() {
      return throwable -> chuck(throwable);
    }
  
    /** Cast from A to B with special treatment of the Number classes. */
    public static <A, B> B cast(A v, Class<B> to) {
      if (Number.class.isAssignableFrom(v.getClass())) {
        if (eq(Integer.class, to)) {
          return (B) ((Object) (((Number) v).intValue()));
        } else if (eq(Long.class, to)) {
          return (B) ((Object) (((Number) v).longValue()));
        } else if (eq(Double.class, to)) {
          return (B) ((Object) (((Number) v).doubleValue()));
        } else if (eq(Float.class, to)) {
          return (B) ((Object) (((Number) v).floatValue()));
        } else if (eq(Short.class, to)) {
          return (B) ((Object) (((Number) v).shortValue()));
        } else if (eq(Byte.class, to)) {
          return (B) ((Object) (((Number) v).byteValue()));
        } else {
          return (B) v;
        }
      } else if (to.isAssignableFrom(v.getClass())) {
        return (B) v;
      } else {
        throw new ClassCastException(v.getClass().getName() + " is not of type " + to.getName());
      }
    }
  
    /** Widening cast. */
    public static <A> List<A> widen(List<? extends A> xs) {
      return (List<A>) xs;
    }
  
    /** Widening cast. */
    public static <A> Optional<A> widen(Optional<? extends A> xs) {
      return (Optional<A>) xs;
    }
  
    public static <A> Function<A, A> ifThen(A predicate, A b) {
      return a -> predicate.equals(a) ? b : a;
    }
  }